The present invention relates generally to sliver opening devices and, more particularly, to means for enclosing the opening cylinder within the housing of the device.
Such sliver opening devices, which are described in numerous publications, especially in conjunction with open-end rotor spinning machines, have long been known and have proven themselves in practice.
For example, German Patent Publication DE 38 14 514 C2 describes a sliver opening device with an opening cylinder fixed via its bearing shaft in a bearing bracket of a spinning box housing. A roller bearing and a base which is surrounded by a replaceable annulus of opening elements (e.g., card clothing or the like) are arranged on the bearing shaft. The annulus is fixed between an axially movable cover disk and an abutment flange of the base. The cover disk is biased axially via a screw bolt which acts on an intercalated spring element.
During the spinning process the opening cylinder and the annulus rotate as a unit in an interior recessed area of an opening-cylinder housing and thereby function to open a supplied sliver into individual fibers. The individualized fibers are then fed to a spinning rotor rotating at a high speed in a rotor housing. The rotating opening cylinder is covered at its front (outward) side by a safety plate fixed on the opening-cylinder housing which plate prevents operating personnel from being able to inadvertently touch the frontal cover disk of the rotating opening cylinder and injure themselves thereby.
Even though the known sliver opening devices in principle have proven themselves in practice, their structural components have a few disadvantages, e.g. a relatively great susceptibility to form fly or fluff from the opening of the sliver.
For example, the problem can occur in the known sliver opening devices that fiber fly collects during the spinning process between the safety plate arranged stationarily on the opening-cylinder housing and between the rotating cover disk. This fiber fly can build up in the further course of the spinning process to a rather large fiber clump and then result in considerable disturbances, e.g. blocking the opening cylinder. Specifically, the fiber fly, which is unavoidable in spinning mills, is sucked into the opening-cylinder housing due to the vacuum therein and settles generally between the stationary safety plate and the rotating cover disk.
German Patent Publication DE-AS 23 29 223 teaches a sliver opening device in which the amount of infiltrated secondary air flowing in through a circulation slot into the opening-cylinder housing is to be limited by a sealing arrangement between a rim edge of the opening cylinder and the wall of the opening-cylinder housing to a value which takes into account certain technological requirements as well as the expenditure of energy. Among other things, a stepped, labyrinth-like seal is described as a possible embodiment for such a sealing arrangement. The sealing arrangement is located on the back side of an opening-cylinder housing closed in a hood-like manner on the front.
However, there is the danger in the case of opening-cylinder housings designed in this manner that combed-out individual fibers get in the area between the closed front wall of the opening-cylinder housing and the flanged wheel of the opening cylinder and become compressed therein over the passage of time. This process can result subsequently in considerable disturbances in normal operation of the device, but is generally noticeable too late from the outside, whereby these known sliver opening devices have not been accepted in practice.
Moreover, German Patent Publication DE 41 21 387 A1 teaches a support disk bearing for open-end spinning apparatus in which the outward sides of the support disks are aerodynamically improved. That is, convexly curved covers are arranged on the side surfaces of these support disks to reduce the air vortices in the area of the rotating side surfaces of the support disks during operation. A measurable lowering of the energy consumption during the operation of such support disk bearings was able to be achieved with these aerodynamically improved support disks.